The present embodiments relate to identifying and/or locating an RFID transponder.
With Radio-Frequency Identification (RFID) technology, objects may be identified and located. An RFID system includes an RFID transponder (e.g., \attached to an object). In addition, the RFID system includes one or more RFID readers, which may send out a corresponding query signal. The query signal is sent out in the form of an alternating magnetic field. This alternating field may also serve the purpose of supplying the RFID transponder with energy. In response to the query signal, the RFID transponder sends back a response signal to the RFID readers. Based on this signal, the RFID transponder may be clearly identified.
If there are a number of RFID readers in a space that are sending out query signals, a collision of the signals from the RFID readers and the RFID transponder may occur. If the query signals sent by a number of RFID readers arrive at the RFID transponder at different points in time, and a number of command sequences for reading out an identification are destructively overlaid, the necessary depth of modulation is not achieved and the identification may not be read out.
In this respect, US 2006/0261161 A1 describes a commodity information registering apparatus, which may include two RFID readers. The commodity information registering apparatus also includes a POS terminal with a processor, with which the RFID readers may be activated for sending out a query signal.
Moreover, US 2010/052856 A1 discloses an RFID system that serves for triangulation. The system may have three RFID readers and a control device, connected to the RFID readers. With the RFID readers, RFID transponders may be identified and located. Using the control device, the RFID readers may be sequentially activated in order to send out a query signal.